The savage storms in that passed through parts of Alabama, Mississippi, Tennessee and Virginia on Wednesday knocked out power to the Browns Ferry nuclear power plant, about 30 miles west of Huntsville, Ala.

The Tennessee Valley Authority-owned plant had to use seven diesel generators to power the plant's three units. The safety systems operated as needed and the emergency event was classified as the lowest of four levels, the U.S. Nuclear Regulatory Commission said.

All three units at TVA's 3,274-megawatt plant shut down around 5:30 p.m. Wednesday. External power was restored quickly to the plant but diesel generators remained running Wednesday evening, Reuters reports, citing a Nuclear Regulatory Commission spokeswoman.

"The Browns Ferry units are among 23 U.S. reactors that are similar in design to the crippled Fukushima Daiichi nuclear plant in Japan where backup generators were swept away in the tsunami that followed the massive earthquake on March 11," Reuters reported.

Severe though the natural disaster was, it hardly matched the destruction -- in property and lives -- of the March 11 quake and tsunami in northern Japan, which is thought to have killed more than 20,000 people and caused at least partial meltdowns at several of the Fukushima reactors.

That event brought renewed attention to nuclear safety in the U.S., where many plants rely on the same model of reactors found at the Fukushima plant. Experts say that lax regulation and the possibility of earthquakes and other natural disasters put U.S. plants at risk.